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Flashcards in Cardiac Embryology Deck (22)
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ascending aorta and pulmonary trunk derived from

Truncus arteriosus


Smooth parts of left and right ventricles (outflow) derived drom

bulbis cordis


Trabeculated left and right ventricles derived from

primitive ventricle


Coronary sinus derived from

left horn of sinus venosus


Smooth part of right atrium derived from

Right horn of sinus venosus


superior vena cava derived from

Right common cardinal vein and right anterior cardinal vein


What structure divides the truncus arteriosus into the aortic and pulmonary trunks? What is the cellular origin of this structure?

Aorticopulmonary (spiral) septum--> derived from neural crest cells


What 3 defects can occur due to pathologic aorticopulmonary septum formation?

1. Transposition of great vessels (failure to spiral)
2. Tetralogy of Fallot (skewed septum development; blocs off some of pulmonary artery outflow)


Which fetal blood vessel has the highest oxygenation? What is the path through fetal circulation

Umbilical vein (highest oxygen; 80%)--> ductus venous (bypasses portal circulation in liver)--> IVC--> Right atrium to left atrium via Foramen ovale--> Ductus arteriosus to circulation
Umbilical arteries branch off illiacs to go back to placenta


What causes the ductus arteriosus to close?

Increased oxygen due to first breaths--> increased O2 in aorta--> decreased prostaglandin (PGE2) synthesis = closure of ductus arteriosus


What causes the foramen ovale to close?

First breaths--> increased O2 in pulmonary vasculature--> dilation and decreased resistance--> increased left atrial pressure--> snaps foramen ovale shut


What structure first forms between the top of the heart and the dorsal endocardial cushion when the interatrial septum is developing?

Septum primum


What two opening derive from the septum primum? Which one doesnt persist for long?

1. Foramen primum (the one formed before septum primum fuses with endocardial cushion fully; goes away once they fuse)
2. Foramen secundum --> this one remains


Which atrium does the Septum secundum form from? What structure does it create?

Right atrium--> creates the foramen ovale

*fetal blood bypasses pulmonary circulation by going through foramen ovale and foramen secundum


What structure composes the valve that prevents backflow of blood from the left to right atria through the foramen ovale in fetal circulation?

portion of the septum primum that fused with the endocardial cushion


What herat development issues are seen with Trisomy 21?

Endocardial cushion defects--> growths from these separate atria from ventricles and contributes to both atrial separation and membranous portion of the interventricular septum


What four structures does fetal erythropoiesis occur in?

1. Yolk sac (3-10 weeks)
2. Liver (6wks - birth)
3. Spleen (15-30 weeks)
4. Bone Marrow (22wk-adult)
*Young Liver Synthesizes Blood


maxillary artery comes from which aortic arch

1st arch

* "1st arch is maximal"; is branch of external carotid


common carotid artery and proximal internal carotid artery come from which aortic arch

3rd arch


aortic arch (on left) and proximal subclavian on the right come from which aortic arch

4th arch


2nd aortic arch derivatives (2)

1. Stapedial arch
2. hyoid artery


6th aortic arch derivatives (2)

1. proximal part of pulmonary arteries
2. ductus arteriosus (on left only)

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